IN-VIVO T-CELL CLONAL AMPLIFICATION AT TIME OF ACUTE GRAFT-VERSUS-HOST DISEASE

In a series of patients transplanted with HLA-matched allogeneic bone marrow grafts (alloBMT), we previously showed that a few T-cell recept or (TCR) V alpha and V beta gene segment transcripts were overexpresse d in skin compared with blood at the time of acute graft-versus-host d isease (aGVHD). Here, in one selected patient with overexpressed V bet a 16 and V alpha 11 transcripts in skin, we analyzed the junctional va riability of these transcripts in donor blood, patient blood, and skin collected at aGVHD onset. A unique junctional region sequence account ed for 81% of in frame V beta 16 transcripts (13 of 16) in skin and 59 % (73 of 22) in patient blood. Similarly, two recurrent junctional reg ion sequences were found in skin V alpha 11 transcripts, one accountin g for 66% (21 of 32) and the other for 16% (5 of 32). These recurrence s were also found in patient blood (36% and 15% of V alpha 11 transcri pts, respectively). To extend our analysis, a polymerase chain reactio n (PCR)-based method was used to precisely determine TCR beta transcri pt length in run-off reactions using uncloned bulk cDNA samples. All V beta-C beta PCR products analyzed in donor blood, as well as the majo rity of those analyzed in patient blood, included transcripts with hig hly diverse junctional region sizes. As expected from the sequence dat a, most V beta 16-C beta PCR products in skin and patient blood were o f the same size (ie, same junctional region). In addition, V beta 3, V beta 5, and V beta 17 transcripts in skin were shown to display highl y restricted size variability. The clonality of the V beta 16-C beta a nd V beta 17-C beta transcripts was further supported by the results o f run-off reactions using 13 J beta specific primers. We have identifi ed several recurrent TCR transcripts in skin, some of them also presen t in patient blood. These data support the view that several T-cell su bpopulations are clonally expanded in vivo at the time of aGVHD onset in this case of related HLA-matched alloBMT. (C) 1994 by The American Society of Hematology.